Donald Trump unfazed by criticism, won't back down, saying, 'Somebody has to say what's right'

U.S. Republican presidential candidate Donald Trump speaks during a campaign stop in Spencer, Iowa, on Dec. 5, 2015Reuters

Despite the avalanche of criticism cascading on him on his latest rant against terrorism, leading Republican presidential candidate Donald Trump said he is unfazed and not backing down.

Elaborating on his earlier suggestion that all Muslims should be banned from entering the United States until the country can get a grip on Islamic terrorism, Trump said this is just a "short-term" measure, Newsmax reported.

Interviewed on Tuesday on ABC's "World News Tonight," Trump said his proposed ban on Muslim entry into the U.S. "could be very quickly if our country could get its act together."

"We need toughness and smartness, and we have to do it quickly," he quipped.

Show host Barbara Walters asked Trump if he regrets having made the suggestion, considering the volume of criticism he received, including from his own Republican Party.

"Not at all," he said. "We have to do the right thing. Somebody in this country has to say what's right."

Trump said he does not believe that his idea will cause problems with Muslims in the United States, claiming that his own friends who are Muslims agree with him "100 percent."

"They [terrorists] knocked down the World Trade Center – they tried doing it twice," Trump said. "Other things have happened. ... There are people that have tremendously bad intentions. We have to be tough, we have to be smart and we have to be vigilant.

"I'm the worst thing that ever happened to ISIS," he added.

On why all the other Republican presidential candidates are criticising him for his idea, Trump said, "They're running against me. For the most part, they have no poll numbers. I'm leading by a lot. They get it. They're trying to get publicity for themselves."

Donald Trump's lead nearly doubles in New Hampshire

Despite all the negative publicity he has been receiving, Trump is even expanding his already wide lead in the Republican nomination race.

In the latest CNN/WMUR poll conducted by the University of New Hampshire Survey Center, Trump has increased his lead to 32 percent, up 6 points since September, CNN reported.

Florida Sen. Marco Rubio is a distant second at 14 percent. New Jersey Gov. Chris Christie is at third place in the new poll with 9 percent, followed closely by former Florida Gov. Jeb Bush (8 percent), Ohio Gov. John Kasich (7 percent), Texas Sen. Ted Cruz (6 percent), and both businesswoman Carly Fiorina and former neurosurgeon Ben Carson at 5 percent. Fiorina has dropped 11 points since the September poll.

CNN/ORC surveys in Iowa and nationally also showed Trump with growing leads over the rest of the GOP field.

On who among the Republican bets can best deal with ISIS, Trump is the runaway choice of voters, getting 33 percent. His closest rival in this category is far behind, Bush who only garnered at 11 percent.

In case Trump fails to get nomination of the Republican Party for the November 2016 presidential election, an overwhelming majority of his supporters say they would still vote for him if he ran as an independent, USA Today reported.

In a new USA TODAY/Suffolk University poll, 68 percent of Trump's supporters say they would vote for the billionaire businessman even if he quits the Republican Party and ran as an independent.